docs: def load_manifest(app, filename='manifest.json'):
      '''Load an assets json manifest'''
      if os.path.isabs(filename):
          path = filename
      else:
          path = pkg_resources.resource_filename(app, filename)
      with io.open(path, mode='r', encoding='utf8') as stream:
          data = json.load(stream)
      _registered_manifests[app] = path
      return data